Development and Usability of the “FORTEe Get Strong” App to Promote Physical Activity and Health Awareness in Children and Adolescents With Cancer During Intensive Treatment Using an App-Based Approach: Mixed Methods Study

Mareike Kuehn   ^{1, 2 *} , MSc ;   Lena Wypyrsczyk   ^{1, 2 *} , MSc ;   Francesca Lanfranconi   ³ , MD, PhD ;   Adriana Cristina Balduzzi   ^{4, 5} , Prof Dr ;   Hayley Marriott   ⁶ , MSc ;   Alba Solera-Sanchez   ⁶ , PhD ;   Joachim Wiskemann   ⁷ , Prof Dr Phil ;   Nikolai Bauer   ⁷ , MEd ;   Nina Karguth   ⁸ , MSc ;   Barbara Heißerer   ⁸ , PhD ;   Norbert W Paul   ⁹ , MD, PhD, Prof Dr rer medic ;   Rodolf Mongondry   ¹⁰ , MSc ;   Wilhelm Bloch   ¹¹ , Prof Dr Med ;   Katie Rizvi   ¹² ;   Martin Kaj Fridh   ¹³ , PhD ;   Eva S C Ramos   ¹⁴ , MSc ;   Carmen Fiuza-Luces   ¹⁵ , PhD ;   Miriam Götte   ^{16, 17} , PD Dr rer med ;   Gabriele Gauß   ¹⁷ , MA ;   Filippo Spreafico   ^{18, 19} , MD ;   Barbara Konda   ²⁰ , BSc ;   Milica Stefanović   ²¹ , MD, PhD ;   Elias Dreismickenbecker   ^{1, 2} , MSc ;   Marie A Neu   ¹ , Dr med ;   Joerg Faber   ¹ , Prof Dr med ;   FORTEe Consortium   ²²

¹ Childhood Cancer Center Mainz, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany

² Department of Sports Medicine, Prevention and Rehabilitation, Institute of Sport Science, Johannes Gutenberg-University Mainz, Mainz, Germany

³ Fondazione Monza e Brianza per il bambino e la sua mamma, Centro Maria Letizia Verga, Monza, Italy

⁴ School of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy

⁵ Pediatrics, Fondazione IRCCS San Gerardo dei Tintori, Monza, Italy

⁶ School of Sport, Nutrition and Allied Health Professions, Oxford Brookes University, Oxford, United Kingdom

⁷ Department of Medical Oncology, Working Group Exercise Oncology, a partnership between DKFZ and University Medical Center Heidelberg, Heidelberg University Hospital and National Center for Tumor Diseases, Heidelberg, Germany

⁸ Concentris research management GmbH, Fürstenfeldbruck, Germany

⁹ Institute for the History, Philosophy and Ethics of Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany

¹⁰ Centre de Lutte Contre le Cancer, Centre Léon Bérard, Lyon, France

¹¹ Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Cologne, Germany

¹² Youth Cancer Europe, Cluj-Napoca, Romania

¹³ Department of Pediatrics and Adolescent Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark

¹⁴ Department of Sport Sciences, Faculty of Medicine, Health and Sports, Universidad Europea de Madrid, Madrid, Spain

¹⁵ Research Institute Hospital 12 de Octubre, Madrid, Spain

¹⁶ West German Cancer Center, Essen University Hospital, Essen, Germany

¹⁷ Hematology and Oncology, Clinic for Pediatrics III, Essen University Hospital, Essen, Germany

¹⁸ Oncology Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy

¹⁹ Pediatric Oncology Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy

²⁰ Forma 3D Ltd, Ljubljana, Slovenia

²¹ Ljubljana University Medical Centre, Ljubljana, Slovenia

²² See Acknowledgments

*these authors contributed equally